1. Field of the Invention
The invention relates to semiconductor memory cells and more particularly to sense latches used to read and write such memory arrays.
2. Related Inventions
U.S. patent application Ser. No. 866,126 filed Dec. 30, 1977 and assigned to the same assignee as the present invention, is directed to a bipolar dynamic array cell with which the present invention is particularly useful.
A U.S. patent application filed on even date herewith by the same inventor and assigned to the same assignee as the present invention is directed to a current source particularly useful with such a bipolar dynamic array.
3. Description of the Prior Art
U.S. Pat. No. 3,993,917 issued Nov. 23, 1976, to H. L. Kalter and assigned to the same assignee as the present invention describes a parameter independent field effect transistor sense amplifier for sensing stored information in a semiconductor memory system with the amplifier capable of sensing very small voltage signals provided by charges stored in single field effect capacitor memory cells. This amplifier comprises a pair of cross coupled FET devices coupled to a pair of sense lines by clock signal responsive switching devices and discharges one bit line through one field effect transistor while holding the other bit line as its precharged level.
U.S. Pat. No. 4,054,865 describes still another sense latch circuit. In this arrangement a plurality of different amplifiers corresponding to the number of columns of memory cells in the array is required.
U.S. Pat. No. 4,010,453 to S. C. Lewis and assigned to the same assignee as the present invention discloses still another differential sense amplifier for semiconductor memory cells. In this case however, both bit lines are arranged to lose charge simultaneously.
U.S. Pat. No. 3,678,473 issued July 18, 1972, to S. Walstrom and assigned to Shell Oil shows a FET sense latch in which the bit lines are preset and the latch is switched on, after the cell is read, to pull down the bit line with the lower charge, the other bit line being left substantially untouched.
Other sense amplifiers for semiconductor memories are shown in U.S. Pat. No. 3,949,381 and U.S. Pat. No. 3,967,252.